Compared to conventional ceramics, the zirconia ceramic has the characteristics of better corrosion resistance, higher hardness, and higher strength, and thus is widely used. The toughness of the zirconia ceramic can reach up to 5 to 6 MPa m1/2. Though the toughness of the zirconia ceramic is higher than that of other conventional ceramics, when fabricated into a large-area exterior part, the zirconia ceramic has the disadvantages of lacking break resistance, having a white color itself, and being too monotonous, etc. However, because the ceramic used as an exterior part needs to simultaneously satisfy the conditions of high toughness, break resistance, and black chromaticity, the existing zirconia ceramic products all fail to meet the requirements of the ceramic to be used in the exterior part. Accordingly, the application of the zirconia ceramic in the exterior part is severely affected.
Because the yttrium-stabilized zirconia powder in the market has been very mature already, the existing toughening technical solutions are all established based on stabilization using yttrium. In the existing toughening technologies, solutions such as the phase transition and the second-phase toughening are most commonly used. However, such solutions are either used only for white ceramics, or fail to achieve the toughening and break-resistant effects when blackening is achieved. For example, though the Mg-stabilized TZP ceramic mentioned in the patent application CN1170787C has a certain degree of toughening effect, the toughening effect is not apparent. Further, the strength of the prepared sample is relatively low and only has a value of approximately 590 MPa, and the large-area exterior part sheet prepared by using a ceramic with such strength is easy to break. Thus, the ceramic with the aforementioned strength can hardly be prepared into a large-area sheet. Further, the ceramic is white, and the application range is also relatively small.
Accordingly, a zirconia ceramic that has excellent properties of high toughness, high break resistance and high blackness and a preparation method therefor are currently highly desired.